Sir Malcolm used an appearance on the BBC's Sunday Politics Scotland programme to criticise VisitScotland for not drumming up enough interest.

"In 2009, the organisers went to America and Australia and promoted that gathering," he said.

"They went to every single Scottish games they could find and went round - tapping the boards, leaflets, you name it - promoting it. I'm not sure if VisitScotland and the people organising Bannockburn have actually done that."

Sir Malcolm also said the decision to hold UK Armed Forces Day in Stirling on the same weekend had caused "confusion" among foreigners considering visiting for Bannockburn Live.

"There's nothing worse than a confused ancestral tourist or ancestral Scot because they're the ones putting the money into this," he said.

Organisers have been wary not to repeat the failures that led to some £700,000 being wiped from the public purse during a similar event in 2009.

The Gathering in Edinburgh attract 47,000 people and was said to have generated £8 million for the city's economy, yet administrative blunders hit the taxpayer and left 100 small businesses out of pocket.

Murdo Fraser, Scottish Conservative tourism spokesman, said yesterday there were warning signs for the Bannockburn commemorations, now less than four months away.

"What's concerning is ticket sales haven't gone very well so far. A lot of public money has gone into this event - we need to make it a success," he said.

"The Scottish tourism industry is relying on it being a success and it's going to be very disappointing if it doesn't live up to expectations."

Yet supporters of the event said 90 per cent of the most expensive tickets fhave been sold and noted that the major marketing push is yet to begin.

Bruce Crawford, SNP MSP for Stirling, said he had "absolutely no concerns" about Bannockburn Live and called on critics to stop "talking things down and being negative".

"This will be a break-even event and that's the way it should be. It has been well managed," he said.

"Visist Scotland are the right organisation to be taking this forward. They've got the marketing skills and the ability to make this really take off."

He denied that there was a division between Unionists promoting UK Armed Forces Day and Nationalists backing Bannockburn Live.

Riddell Graham from VisitScotland said: "It was always the case that the promotional activity would be built up as we worked towards the event itself. History tells us that events like this there's a big rush at the end."